Press tools of this kind are, inter alia, known as press chains, press loops or press rings and are used, for example, to join tube pieces. For this purpose, a deformable sleeve, referred to as a press fitting system, can be used as a connector. In this case, the joint is usually produced by the tube pieces being inserted into the press fitting system by one end in each case and the press tool subsequently pressing on the press fitting system once in the region of overlap with one tube end and once in the region of overlap with the other tube end.
By means of the press tool, a forming force is exerted on the press fitting system which undergoes a change in shape as a result, and therefore a press connection between the press fitting system and the tube end received therein is produced. Conventionally, the press tool encompasses the press fitting system by its pressing jaws and exerts the forming force on the outer circumference of the press fitting system.
The pressing jaws normally form a mold for the workpiece to be deformed, since they directly press on the workpiece to be deformed. By means of the design as a mold, a targeted three-dimensional change in the shape of the workpiece to be deformed is intended to be effected on the target contour predefined by the mold.
However, the actual change in shape usually often deviates therefrom, since it additionally leads to one or more unintentional three-dimensional changes in shape. These deformations are advantageous at those points on the workpiece to be deformed that are not acted on by the pressing jaws. The material can flow herein during the pressing process and may stack up to form an undesired shape. An outwardly protruding, relatively pointed projection may be produced in this way, which projection considerably limits the functionality of the surface.
For example, using the surface as a contact surface for a sealing element is only possible to a very limited extent or not at all, since the sealing effect is reduced by such a projection and in addition the service life of the sealing element is impaired.